Organs to print. It reads and sounds utterly incongruous. Even suggesting it less than a decade ago would likely have resulted in a patronising chuckle and perhaps some humorous commentary about technophiles. Yet today that is precisely what is occurring in cutting edge research.
The possibilities of printed organs using the recipients own cellular material is now emerging from a far off potential and into reality. Patients dying of organ failure could receive organs printed from their own tissue averting both rejection issues and often terminally long organs transplant lists.
In recent years regenerative medicine has already implanted lab-grown skin, trachea’s and bladders into patients. These body parts were grown slowly using artificial scaffolds and living human cells. 3D-printing technology however, offers both greater speed and computer-guided precision in printing living cells layer by layer to make replacement skin, body parts and perhaps eventually organs such as hearts, livers and kidneys.
“Bioprinting organs for human uses won’t happen any time soon. But for tissues we’ve already implanted in patients — structures we’ve made by hand — we’re now going back to those tissues and saying ‘We know we can do better with 3D printing.”
– Tony Atala, director of the Wake Forest Institute for Regenerative Medicine in Winston-Salem, N.C.
[pullquote] “The smart aortic graft has the potential to not only extend a patient’s life, but also to provide them with mobility, comfort and a reduced need for carers.”
-Dr. Philip Breedon [/pullquote]
Already though 3D printing has moved from printing vascular structures to skin and now even heart tissue. The key difficulty arises in the number of cell types in the tissue being printed as well as their structural arrangement. For example skin is largely one cell type and is layered in flat levels so its relatively easy to print. Blood vessels are tubular and made up of two cell types and so pose a larger challenge while larger hollow organs like the stomach and bladder each with integrated functions and interactions with other organs are significantly more difficult to print.
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Finally liver, kidneys and the heart pose the ultimate problem with very large numbers of differentiated cells, highly articulated structures and multiple function, integrations and complexity. But some labs think they can dispense with the artificial scaffold, which can be problematic in both injecting and dissolving, by talking advantage of cells self organising capacity and simply layer the cells in the correct order.
“If you do what we do with putting cells in the right place, you don’t start with anything structural to hold things up. For us, the challenge is the strength and integrity of the structure.”
– Keith Murphy, chairman and CEO of Organovo, a startup San Diego-based company.
But the biggest challenge so far is the seeding of blood vessels through the printed organ to allow it nutrient and blood supply. What is this technologies probable success in creating functioning organs? Organovo seems highly confident listing itself on the NYSE in July of 2013 and gathering fresh investors despite the bearish stock market.
And 3D printing is not solely restricted to organic based structures, but also artificial prosthesis as well. Researchers at Nottingham Trent University (NTU) and Nottingham University Hospitals NHS Trust in the UK have designed a 3D-printed electronic smart pump to assist damaged or diseased hearts to function better.
According to the NTU website, the pump takes the form of an aortic graft, manufactured from an electronically sensitive ‘smart material’ surrounding a woven tube. It is powered by a small battery which causes the smart material to expand when an electric current is applied. This artificial 3D printed graft would replace a piece of the heart’s large artery. It would contract and expand in response to the hearts own contractions and expansions effectively controlling the diseased heart’s blood flow. The smart pump can shrink to increase circulation to the heart and also expand to deliver oxygen to the rest of the body. By using MRI scans, the researchers believe that they will be able to customise their pumps to fit the size and shape of each individual patient.
The system once completed will be a self-contained unit which no longer requires that patients be hooked up to external equipment. Dr. Philip Breedon, the research team leader and an expert in smart technologies at NTU’s School of Architecture, Design and the Built Environment, explains how the pump can both increase the mobility of patient’s suffering from heart disease as well as saving countless lives:
“This device could really be ground breaking and more effective than any other therapy currently being used around the world. Chronic heart failure is a major health challenge and up to 40 per cent of sufferers die within the first year. The best form of treatment is a heart transplant, but the demand by far outweighs the supply as around 160,000 people require one in Europe each year, but only 600 donor hearts are available. The technology currently used to help people with acute heart failure can only be used for a few days and involves the patient being attached to large external machines which need to be plugged into the mains power supply. The smart aortic graft has the potential to not only extend a patient’s life, but also to provide them with mobility, comfort and a reduced need for carers.”
So cybernetic like fixtures like the NTU smart pump could also allow heart patients far better quality of life and buy valuable time until transplants or printed hearts are available. And it doesn’t stop with just the heart. The recent ‘home’ printing of prosthetic limbs using MakerBot Replicator-type home 3-D printer is both promising and controversial. Criticism of the practice has been that the scanning process to create a comfortable fit is not always ideal or possible making for a generic fit that does not always fit or work well at the joining interface with the body. But in the third world the choice between a mediocre prosthesis and none makes this a far more attractive option, especially when added to the lower price point where knees have been made for as little as $20 U.S.
The rapidly declining price of laser scanning and its technology – combined with 3D printings’ increasingly cheaper price point is music to amputees ears and signals a time of far less capital investment per prosthesis by medical organisations. And that means much greater access for the worlds poor and disadvantaged.
Some researchers though, postulate that experimenting with printing such relatively simple tissues as cartilage, which does not need extensive access to blood vessels to thrive may well be the entry model for a real mass adoption of 3D printing by the medical industry . A Scripps Translational Science Institute researcher, Darryl D’Lima, who is involved in a project to print cartilage, told NYT in a separate article.
“Printing a whole heart or a whole bladder is glamorous and exciting, but cartilage might be the low-hanging fruit to get 3-D printing into the clinic.”
Other firms such as Organovo are printing strips of various tissues for invitro experimental use or layers of liver cells for testing. Using 3D printers the University of Illinois is building “biobots,” which are miniature inchworms made of cardiac muscle cells that slide forward as the cells beat. These ingenious devices could travel around within a patient’s body to deliver drugs or find and destroy toxins.
The prodigious list of medical devices already made by a technology still so wet behind the ears is staggering. Lives by the thousands are being saved or greatly improved by 3D printing in medicine and at the risk of sounding theatrical, this is truly only the beginning.